The present invention generally relates to a storage system, a volume allocation method and a management apparatus, and can be suitably applied to a storage system that virtualizes a storage apparatus into a plurality of virtual storage apparatuses.
In recent years, server virtualization technology for virtualizing physical servers is becoming popular. The server virtualization technology is technology for realizing a physical server in a software-like program execution environment (virtual server). For instance, the server virtualization technology is realized as server virtualization software or hypervisor. As described above, nowadays, an MPU (Micro Processing Unit) of the physical server has hardware functions for realizing the server virtualization technology.
With the server virtualization technology, since a plurality of virtual servers can be operated with a single physical server, the number of physical servers to be actually used can be consequently reduced, and effects such as facilitation of hardware maintenance management and cost reduction are expected. In addition, with the server virtualization technology, when the server virtualization software creates a virtual server, it sets the capacity or ratio of the physical resource (CPU (Central Processing Unit), memory, interface, etc.) to be used by that virtual server, and creates a virtual server having the hardware specification based on this setting.
Meanwhile, storage virtualization technology is also becoming popular for the purpose of facilitating management and reducing operation costs. The storage virtualization technology includes modes that overlap with the server virtualization technology, but also includes different modes. The storage virtualization technology can be broadly classified into three modes; namely, a mode of treating a plurality of physical storage apparatuses (physical storages) as a single virtual storage apparatus, a mode of partitioning a physical resource of a single physical storage and treating such partitions as a plurality of virtual storage apparatuses (virtual storages), and a mode of allocating a physical resource that is being actually used to a plurality of virtual storages (the ensuing explanation primarily focuses on the third mode described above). When partitioning the physical resource of the physical storage, the physical resource to be partitioned includes, in addition to disk devices, a disk cache memory and a communication bandwidth of a fibre channel.
The storage virtualization technology of the third mode described above is provided based on a so-called dynamic storage area allocation function that realizes dynamic capacity expansion by dynamically allocating a storage capacity to a virtual volume. A physical resource (storage area of disk device) is allocated to a virtual volume set with this attribute only in an area that was previously accessed. Thus, hardware resources can be efficiently used in this kind of storage virtualization technology.
As this kind of dynamic storage area allocation function, technology is proposed for acquiring logical volume configuration information for each allocated logical volume, setting the other logical volumes in the same logical volume group including the allocated volume, selecting the logical volume having the lowest I/O load among the allocation candidate volume group, and removing the other logical volumes of the same volume group from the allocation target (for instance, refer to Japanese Patent Laid-Open Publication No. H10-320126).
Meanwhile, the conventional storage virtualization technology gives no consideration to the server virtualization technology, and there is a problem in that it is not compatible with virtual servers.
For example, with the server virtualization technology, there are cases where the physical resource is shared, and if a volume of the physical storage is allocated to a virtual server with the same method as allocating the volume to the physical server, there is a problem in that the physical resource will be allocated excessively.
In addition, the conventional storage virtualization technology is only able to manage a physical host bus adapter, and there is a problem in that a corresponding physical resource cannot be allocated to the configuration of the virtual server such as not being able to manage a virtual host bus adapter. Like this, with the conventional technology, there is a problem in that the operational efficiency of the storage apparatus will deteriorate.